Sleep apnea is a serious sleep disorder that occurs when a person’s breathing is interrupted during sleep. People with untreated sleep apnea stop breathing repeatedly during their sleep, sometimes hundreds of times. This means the brain — and rest of the body — may not get enough oxygen.

Types of sleep apnea

There are two types of sleep apnea.

  • Obstructive sleep apnea, which is the more common of the two forms. It is caused by a blockage of the airway, usually when the soft tissue in the back of the throat collapses during sleep.
  • Central sleep apnea occurs when the brain fails to signal the muscles to breathe due to instability in the respiratory control center.

Irritated ManSymptoms

Are you experiencing any of these signs and symptoms?

  • Loud snoring
  • Episodes of breathing cessation during sleep witnessed by another person
  • Abrupt awakenings accompanied by shortness of breath
  • Awakening with a dry mouth or sore throat
  • Morning headache
  • Difficulty staying asleep (insomnia)
  • Excessive daytime sleepiness (hypersomnia)
  • Attention problems
  • Irritability

Asleep at the wheelThese are the signs and symptoms of obstructive and central sleep apneas. Doctors estimate that 18 million Americans have moderate to severe apnea and 75 percent of them do not know it. Sleep apnea can affect anyone, even children.

Severe apnea can be deadly: starving the brain of oxygen all night quadruples the risk of stroke

Causes of obstructive sleep apnea

Obstructive sleep apnea occurs when the muscles in the back of your throat relax. These muscles support the soft palate, uvula (the triangular piece of tissue hanging from the soft palate), tonsils, side walls of the throat, and tongue.

When the muscles relax, your airway narrows or closes as you breathe in, and you can’t get adequate breath. This may lower the level of oxygen in your blood.

Your brain senses this inability to breathe and rouses you from sleep so that you can reopen your airway. This awakening is usually so brief that you don’t remember it.

You may make a snorting, choking or gasping sound. This pattern can repeat itself all night long. These disruptions impair your ability to reach restorative sleep and you’ll feel sleepy during your waking hours.

People with obstructive sleep apnea may not be aware that their sleep was interrupted and think they sleep well all night.

Causes of central sleep apnea

Central sleep apnea is a less common form of sleep apnea that occurs when your brain fails to transmit signals to your breathing muscles. This means you make no effort to breathe for a brief period. You may awaken with shortness of breath or have a tough time getting to sleep or staying asleep.

Overweight manRisk factors

Certain factors increase your risk of obstructive sleep apnea.

  • Excess weight
  • Neck circumference
  • A narrowed airway
  • Being male, men are twice as likely to have sleep apnea
  • An older adult
  • Family members with sleep apnea
  • Use of alcohol, sedatives or tranquilizers
  • Smoking
  • Nasal congestion


Sleep apnea is a serious medical condition. Complications may include:

  • Sleep-deprived partner
  • Daytime fatigue
  • High blood pressure or heart problems
  • Type 2 diabetes
  • Metabolic syndrome (high blood pressure, abnormal cholesterol, high blood sugar and increased waist circumference)
  • Liver problems
  • Increasing the risk of stroke

Sleep apnea, left untreated for even a few days, can increase blood sugar and fat levels, stress hormones and blood pressure, according to a new study of sleeping subjects. A report of the study’s findings, published in the August issue of The Journal of Clinical Endocrinology & Metabolism.

Woman snoringWhen to see a medical professional

Consult a medical professional if you experience, or if your partner notices, the following:

  • Snoring loud enough to disturb the sleep of others or yourself
  • snoring that’s punctuated by periods of silence.
  • Shortness of breath, gasping for air or choking that awakens you from sleep
  • Intermittent pauses in your breathing during sleep
  • Excessive daytime drowsiness, which may cause you to fall asleep while you’re working, watching television or even driving
  • Any sleep problem that leaves you chronically fatigued, sleepy and irritable.


Your medical provider may make an evaluation based on your signs and symptoms or may refer you to the Knoxville Hospital & Clinics’ Sleep Disorders Clinic.

Tests to detect sleep apnea include:

  • Nocturnal polysomnography. During this test, you’re hooked up to equipment that monitors your heart, lung and brain activity, breathing patterns, arm and leg movements, and blood oxygen levels while you sleep. This test is performed at the Knoxville Hospital & Clinics’ Sleep Lab and is monitored by specialized technicians. The test is noninvasive; the monitors stick to your skin; you have your own private bathroom; and a Sleep Number regular bed.
  • Home Sleep Test. In some cases, your medical provider may order a test to be used at home to diagnose sleep apnea. These tests measure your heart rate, blood oxygen level, airflow and breathing patterns. Home sleep testing is a new service being offered by the Knoxville Hospital & Clinics. Portable monitoring devices don’t detect all cases of sleep apnea, so your medical provider may still recommend a nocturnal polysomnography, even if your initial results are normal.

Diagnosis and therapies

For milder cases of sleep apnea, your doctor may recommend only lifestyle changes, such as losing weight or quitting smoking. If these measures don’t improve your signs and symptoms or if your apnea is moderate to severe, several other treatments are available.

If you have nasal allergies, you doctor may refer you to KHC’s Allergy Services. If you have obstructive sleep apnea, your doctor may refer you to an ear, nose and throat doctor to rule out any blockage in your nose or throat. An evaluation by a heart doctor or a doctor who specialized in the nervous system may be necessary to look for causes of central sleep apnea.

Therapies for obstructive sleep apnea may include a continuous positive airway pressure (CPAP) machine that delivers air pressure through a mask placed over your nose while you sleep. There are also other airway pressure devices, oxygen supplement devices, and oral appliances that may be recommended. Surgery is usually only an option after other treatments have failed.

Home Sleep TestMore about KHC’s new Home Sleep Testing service

The services of Knoxville Hospital & Clinics’ Sleep Disorders Clinic require a referral from a medical professional. So, if you are experiencing any of the symptoms mentioned in this article, begin by scheduling an appointment with one of our Family Medicine providers to discuss your condition.

Home sleep testing is relatively simple and is performed in the comfort of your bedroom. The necessary testing equipment is available at the Sleep Disorders Clinic and provided by Practical Sleep Services, whose technician will instruct the patient on how to use the system.

The equipment is easy to hook up, without help and in about 15 minutes. A belt is clipped around your chest and abdomen, a fingertip is slid into a sleeve that monitors your oxygen level, and a breath sensor hooked over your ears and taped beneath your nose. All three parts plug into a box the size of a pager that sits on the belt on your chest.

Once the test is complete, the equipment is returned and the testing data downloaded. That data is interpreted by the Sleep Disorders Clinic’s medical director, who will prepare a report outlining their diagnosis and treatment recommendations. The report is forwarded to the referring medical provider. The patient’s medical provider will discuss the findings and share his or her recommendations for treatment or may recommend further testing.

Home testing is not recommended for those with heart failure, emphysema, seizures, other sleep disorders and a few other serious health problems. But it’s useful for many people who exhibit the warning signs of apnea, such as waking up exhausted after a full night’s sleep or dozing off at the wheel in bright daylight.